| タイトル | Wake-related sound generation from isolated airfoils |
| 著者（英） | Chalupnik, J. D.; Hodder, B.; Clark, L. T. |
| 著者所属（英） | Boeing Co.|Army Air Mobility Research and Development Lab.|Washington Univ. |
| 発行日 | 1976-01-01 |
| 言語 | eng |
| 内容記述 | A model for the prediction of wake-related sound generation by a single airfoil is presented which assumes that the net force fluctuation on an airfoil can be expressed in terms of the net momentum fluctuation in the near wake of the airfoil. The model predicts a forcing function for sound generation which is related to the spectra of the two-point velocity correlations in the turbulent region near the airfoil trailing edge. Cross spectra were obtained from correlations of the longitudinal and transverse components of turbulence in the wake of a 36-in. chord airfoil in a wind tunnel using x-probe hot-wire sensors. Additional data were obtained from a 10-in. chord airfoil in a free-jet facility. Based on results from these tests, a scaling model was developed using the turbulent boundary-layer thickness as the primary length measure. The model was used to predict the sound radiated from a 2-in. chord airfoil for which acoustical data was available; good agreement was obtained both in level and spectral shape. The single-airfoil result is extended to a rotor geometry, and comparisons are studied for various aerodynamic parameters. |
| NASA分類 | AERODYNAMICS |
| レポートNO | 76A20224 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/444293 |
